1. Field of the Invention
This invention relates to a retainer for holding a swivel ball in the socket of a universal joint yoke.
2. Discussion of the Prior Art
U.S. Pat. No. 4,650,439 discloses a centering apparatus for a constant velocity universal joint in which a pair of outer yokes are pivotally connected to a double inner housing and a centering apparatus is positioned between the outer yokes. The inner end of each yoke defines a ball socket to mate in sliding contact with a swivel ball. The swivel ball is held in the socket by a retainer ring which is threaded to the yoke. Pat. No. 4,650,439 also discloses that it may be desirable in some applications to weld or bolt the retainer ring to the yoke.
However, there were problems with threading, welding and bolting the retainer ring to the yoke. Threading the retainer ring to the yoke required that threads be formed on the yoke and on the retainer ring. It also resulted in the retainer ring having the opportunity to become loosened and possibly removed from the yoke, which could result in failure of the universal joint. Welding the retainer ring to the yoke was also a relatively difficult production process and could result in undesirable hardening of the areas of the yoke and retainer ring adjacent to the weld bead. Hardening not only could make the parts unacceptably brittle but also could result in fatigue failure as the hardened areas were subjected to many loading cycles. Bolting the retainer ring to the yoke would require a relatively great additional mass and space.
All of the retainers discussed above involved a rigid connection to the yoke. However, such a rigid connection is not desirable where a preload is not to be applied to the swivel ball by the retainer. With the threaded and welded retainers, it was possible that the retainers could inadvertently be made to apply a preload to the ball, which would result in greater friction therebetween, generating unwanted heat and accelerated wear.